PRELIMINARY

This document contains information on a product under development at Advanced Micro Devices. The

information is intended to help you evaluate this product. AMD reserves the right to change or discontinue

work on this proposed product without notice.

Publication# 19406

Rev: B Amendment/0

Issue Date: January 1999

1-3

Am79C982

basic Integrated Multiport Repeater (

DISTINCTIVE CHARACTERISTICS

s Fully backward-compatible with existing

IMR/IMR+ device non-managed hub designs

— Pin/socket-compatible with the Am79C980

(IMR) and Am79C981 (IMR+) devices

s Repeater functions comply with IEEE 802.3

Repeater Unit specifications

s Four and eight 10BASE-T port options available

s Low-cost, flexible solutions suitable for

non-managed repeater designs

s Integral 10BASE-T transceivers utilize the

required predistortion transmission technique

s Attachment unit interface (AUI) port allows

connectivity with 10BASE-5 (Ethernet) and

10BASE-2 (Cheapernet) networks, as well as

10BASE-F and/or Fiber Optic Inter-Repeater

Link (FOIRL) segments

s Minimum mode facilitates LED implementation

and provides four LED display options for port

status

s Built-in pulse stretching for carrier sense LED

display

s On-board PLL, Manchester encoder/decoder,

LED display and FIFO

s Expandable to increase number of repeater

ports

s All ports can be separately isolated (partitioned)

in response to excessive collision conditions or

fault conditions

s Network management and optional features are

accessible through a dedicated serial

management port

s Twisted-pair Link Test capability conforming to

the 10BASE-T standard. The receive Link Test

function can be optionally disabled through the

management port to facilitate interoperability

with devices that do not implement the Link Test

function

s Programmable option of Automatic Polarity

Detection and Correction permits automatic

recovery due to wiring errors

s Full amplitude and timing regeneration for

retransmitted waveforms

s Preamble loss effects eliminated by deep FIFO

s CMOS device features high integration and low

power with a single +5 V supply

GENERAL DESCRIPTION

The

basic Integrated Multiport Repeater (bIMR™) chip

is a VLSI circuit that provides a system-level solution to

designing a compliant 802.3 repeater incorporating

10BASE-T transceivers. The device integrates the

Repeater functions specified by Section 9 of the

IEEE 802.3 standard and twisted-pair Transceiver

functions complying to the 10BASE-T standard. The

Am79C982-4 provides four and the Am79C982-8 pro-

vides eight integral twisted-pair medium attachment

units (MAUs), and an attachment unit interface (AUI)

port in an 84-pin plastic leaded chip carrier (PLCC).

A network based on the 10BASE-T standard uses un-

shielded twisted-pair cables, therefore providing an

economical solution to networking by allowing the use

of low-cost unshielded twisted-pair (UTP) cable or

existing telephone wiring.

The total number of ports per repeater unit can be in-

creased by connecting multiple

bIMR devices through

their expansion ports, hence minimizing the total cost

per repeater port. Furthermore, a general-purpose

attachment unit interface (AUI) provides connection

capability to 10BASE-5 (Ethernet) and 10BASE-2

(Cheapernet) coaxial networks, as well as 10BASE-F

and/or Fiber Optic Inter-Repeater Link (FOIRL) fiber

segments. Network management and test functions

are provided through TTL-compatible I/O pins.

The device is fabricated in CMOS technology and

requires a single +5 V supply.